1. Field of the Invention
The present invention relates to a liquid discharge head substrate used for recording information on a recording medium by discharging a liquid, a manufacturing method of the liquid discharge head substrate, a liquid discharge head using the liquid discharge head substrate, and a manufacturing method of the liquid discharge head.
2. Description of the Related Art
A liquid discharge head (also referred to as a head), which is formed by bonding a liquid discharge head substrate (also referred to as a head substrate) to a support substrate so that a liquid such as ink is discharged from a discharge port of the liquid discharge head, is mounted on a liquid discharge apparatus so that information can be recorded on a recording medium.
Japanese Patent Application Laid-Open No. 2007-326240 discusses a silicon head substrate having a through hole penetrating the silicon substrate and also having an electrode on a back side of the substrate. According to this configuration, a head substrate and a support substrate are electrically connected. The head discussed in Japanese Patent Application Laid-Open No. 2007-326240 is illustrated in FIG. 1. A recording element substrate H1100 having an electrode on the backside is electrically connected to a holding base H1200 via an electrode bump H1105.
The head substrate is formed by forming a plurality of head substrates at the same time on, for example, a silicon substrate and segmenting the substrates using a semiconductor manufacturing technique. Thus, if the size of each head substrate is large, the number of the head substrates yielded from one silicon substrate is decreased. As a result, the manufacturing cost will be increased. For this reason, there is a strong demand for smaller head substrates. Further, a small head substrate is also required from the viewpoint of miniaturization of a liquid discharge apparatus on which the liquid discharge head is mounted.
However, according to the head configuration discussed in Japanese Patent Application Laid-Open No. 2007-326240, a certain distance is necessary between an ink supply port and the electrode bump H1105 in preventing ink seepage. Further, the electrode bump H1105 is covered with a sealing compound H1317 that blocks the ink. If the distance is short, the possibility that an electrode is corroded due to the ink seepage is increased. Thus it has been difficult to reduce the area of the head substrate by reducing the distance.